THESE STEPS MUST BE DONE IN SEQUENCE!!
1. Get engine to operating temp
2. Disconnect IAC sensor plug, if you motor stalls, turn the throttle-stop screw in one full turn and restart, repeat as necessary until engine will idle with IAC unplugged.
3. Set idle using throttle stop. Idle speed will vary depending on the modifications made to your engine. Set it where you are comfy with idle speed.'
4. Set TPS anywhere from .96to.98 volts. This done by loosening the mounting screws, and lightly rotating TPS. If you cant obtain the desired range ,you may need to make the mounting holes bigger by drilling them out.
5. TPS wire colors to probe are generally BLACK and GREEN or GRAY/RED and GRAY/WHITE depending on the car
6. Stop engine. Disconnect negative battery terminal for 15-20 minutes. You may wish to tap brakes or flash headlight a few times to ensure you have purged any remaining power in the system. This will reset the computer to factory settings.
7. Reconnect IAC plug
8. Reconnect battery cable to negative terminal
9. Restart engine.
10. If problem persists, inspect for mass air meter problems and possible vacuum leaks.
This info is from Ford Racing. Wording was slightly modified. But this is right off a fax they had sent for idle setting procedure.
IAC - Idle Air Control
TPS - Throttle Positioning Sensor
Hope this was helpful!
http://www.sn95forums.com/Tech/Idle_Fix/index.htm